Figure 1. Myeloid-specific netrin-1 deletion in advanced atherosclerosis alters plaque composition and promotes plaque regression.

A) Experimental design: Ntn1^fl/flCx3cr1^WT and Ntn1^fl/flCx3cr1^CreER+ mice were injected with mPCSK9-AAV and fed Western diet for 20 weeks to establish advanced atherosclerosis. Mice were taken for baseline (BL) measurements or placed on chow diet for 4 weeks to halt atherosclerosis progression and injected with tamoxifen (TAM) to induce Ntn1 deletion (Mø^ΔNtn1) or not (Mø^Ctrl). B) Representative images (left) and quantification (right) of immunostaining for netrin-1 (green), CD68 (red) and DAPI (blue) in cross-sections of aortic root plaques. Scale bar = 50 μm. BL: Ntn1^fl/flCx3cr1^WT n=12, Ntn1^fl/flCx3cr1^CreER+ n=11; TAM: Mø^Ctrl n=13, Mø^ΔNtn1 n=13. C) Representative images and quantification of lesion area of the en face aorta of mice at baseline (n=7) and after TAM + chow diet (n=9). Scale bar = 2 mm. D) Quantification of plaque area in cross-sections of the aortic root at baseline (Ntn1^fl/flCx3cr1^WT n=9, Ntn1^fl/flCx3cr1^CreER+ n=10) and after TAM + chow diet (Mø^Ctrl n=11, Mø^ΔNtn1 n=12). E) Histological classification of aortic root plaques according to Stary: II, moderate lesions (foam cells, SMCs, intracellular lipid accumulation); III, pre-atheroma (foam cells, SMCs, pools of extracellular lipids); IV, atheroma (foam cells, SMCs, large pools of extracellular lipids, necrotic core); V, fibroatheroma (foam cells, SMCs, large pools of extracellular lipids, large irregular necrotic core). BL: Ntn1^fl/flCx3cr1^WT n=11, Ntn1^fl/flCx3cr1^CreER+ n=12; TAM: Mø^Ctrl n=11, Mø^ΔNtn1 n=15). Data are mean ± SEM. P values were determined by (B-D) one-way ANOVA with post-hoc Tukey’s test or (E) Kruskal-Wallis test with Dunn’s correction.